(a) Field of the Invention
This invention relates in general to a signal distribution system. More particularly, it relates to a multiple-room signal distribution system that enables the efficient and cost effective distribution of a received wide band high frequency signal to different areas of a single general location (e.g., different rooms/floors of a single family unit, or different units/floors of a multiple-dwelling-unit).
(b) Description of Related Art
Audio/visual/data (AVD) signal distribution systems generally rely on either a cable network or on free-space propagation to deliver AVD signals, such as television signals, to individual users or subscribers. Cable-based AVD signal distribution systems transmit one or more individual AVD signals or xe2x80x9cchannelsxe2x80x9d over wire, while free-space propagation systems transmit one or more channels through free-space, i.e., in a wireless manner. Most large-scale cable and wireless signal distribution systems broadcast a broadband AVD signal having a plurality of individual AVD signals modulated onto one or more carrier frequencies within a discernable frequency band.
As an introduction to a signal broadcasting system that is capable of incorporating and utilizing the signal distribution system of the present invention, FIG. 1 illustrates at 20 one example of a known wireless AVD signal broadcasting system. The illustrated broadcasting system 20 represents a Direct-to-Home (DTH) satellite communication system 20 having, generally, a transmission station 22, a relay 24, and a plurality of receiver stations, one of which is shown at reference numeral 26. A wireless free-space link provides the communications medium between the transmission station 22, the relay 24, and the receiver station 26. The transmission station 22 includes programming sources 28, control data sources 30, program guide (PG) data sources 34, audio/video/data encoding systems 36, uplink frequency converters 38, and uplink antennas 40. The relay 24 is preferably at least one geosynchronous or geo-stationary satellite. The receiver station 26 shown in FIG. 1 includes a reception antenna/dish 50, a low-noise-block (LNB) 52 connected to the antenna 50, an integrated receiver/decoder (IRD) 54, and a video display device (e.g., television) 60.
In operation, the program source 28 receives video and audio programming from a number of sources, including satellites, terrestrial fiber optics, cable, or tape. The received programming signals, along with data signals from the control data source 30 and program guide (PG) data source 34, are sent to the audio/video/data encoding system 36 where they are digitally encoded and multiplexed into a packetized data stream using a number of conventional algorithms. In a conventional manner, the encoded data stream is modulated and sent through the uplink frequency converter 38 which converts the modulated encoded data stream to a frequency band suitable for reception by the relay/satellite 24. Preferably, the satellite frequency is Ku-band. The modulated, encoded data stream is then routed from the uplink frequency converter 38 to an uplink satellite antenna/dish 40 where it is broadcast toward the satellite 24 over the free-space link. The satellite 24 receives the modulated, encoded Ku-band data stream and re-broadcasts it downward toward an area on earth that includes the various receiver stations 26. The LNB 52 of each receiver station 26 shifts the Ku-band signal down to an L-band signal which is conveyed from the LNB 52 to the IRD 54.
Continuing with further details of the signal broadcasting system 20, FIG. 2 illustrates a more detailed diagram of the receiver station 26 shown in FIG. 1.
As shown, the receiver station 26 includes the antenna 50, the LNB 52, and the IRD 54 which is connected to a display 60 (see FIG. 1). The satellite antenna 50 transfers the received satellite signal to a conventional LNB circuit 52 which then passes the signal to the IRD 54. The IRD 54 includes a tuner 56, a demodulator 58, an FEC decoder 62, a microprocessor 64, a transport IC 66 having a channel demultiplexer 68, a decryption circuit 70, a conditional access module 72, an access card reader 74, a system RAM 76, an audio/video decoder circuit 78 having a random-access-memory (RAM) 80, an audio decoder 82, a video decoder 84, an audio digital-to-analog converter 86, an NTSC encoder 88, an output driver 90, a modem connection 92, a set of microprocessor peripherals 91 (optional), a front panel user interface 94, and a power supply 96, coupled together as illustrated.
The transport IC 66 receives the transport stream of digitized data packets containing video, audio, scheduling information, and other data. The digital packet information contains identifying headers as part of its overhead data. Under control of the microprocessor 64, the channel demultiplexer 68 filters out packets that are not currently of interest, and routes the data packets that are of interest through the decryption circuit 70 and the conditional access module 72 to their proper downstream destination. The decryption circuit 70 provides decryption for the data packets that have been encrypted. The conditional access module 72 provides access control by any conventional means. For example, access control may be achieved by requiring a data packet to have a proper authorization code in order to be passed to the decryption circuit 70 and/or the video decoder 78. The access card reader 74 can interface with an access card (not shown) that will receive the packet authorization code, determine its validity, and generate a code that confirms to the transport IC 66 that the subject data packet is authorized. The conditional access module 72 also contains information necessary to perform a call back operation in which the microprocessor causes the modem 92 to call the satellite provider periodically to report data. The reported data is used for billing purposes and includes information regarding the programs and services that the viewer has accessed via the IRD module 54. Various authorization codes required to perform the callback feature and used to inform the microprocessor 64 as to when callback is desired are determined via the conditional access module 72.
The authorized data of interest are stored in the system RAM 76 for buffering, and the audio/video decoder 78 requests (via the microprocessor 64) the RAM 76 contents as needed. The requested data is routed from the RAM 76 through the transport IC 66 to the audio/video decoder 78. If the request is for video data, video data in the RAM 76 are routed through the transport IC 66 to the video/audio decoder""s DRAM 80 until it is time for the data to be decoded. At that time, the data is routed to the video decoder 84 (which includes on-screen display circuitry) and the NTSC encoder 88. The video decoder 84 reads in the compressed video data from the DRAM 80, parses it, creates quantized frequency domain coefficients, then performs an inverse quantization, inverse discrete cosine transform (DCT) and motion compensation. At this point, an image has been reconstructed in the spatial domain. This image is then stored in a frame buffer in the DRAM 80. At a later time, the image is read out of the frame buffer in the DRAM 80 and passed through the on-screen display circuitry to the NTSC encoder 88. The on-screen display circuitry (located in the video decoder 84) generates the graphics that allow text such as the electronic program guide data to be displayed. The NTSC encoder 88 converts the digital video signals to analog according to the NTSC standard or any other compatible standard, thereby allowing video to be received by and displayed on the display 60 (see FIG. 1).
Turning now to the problems faced and addressed by the signal distribution system of the present invention, to accommodate the viewing tastes of one or more persons simultaneously, it is desirable to be able to receive selected satellite programming at one antenna, and to distribute programming/data in the received satellite signal independently to a plurality of displays/televisions located in separate areas (e.g., separate rooms or floors) of a single family home or multiple-dwelling-unit. Previous systems have been proposed for accomplishing this. In one such system, two IRD units are attached to a single satellite antenna wherein each IRD independently provides selected programming to its associated display/television. The satellite antenna couples the received satellite television signal to a dual-LNB having two LNB circuits for independently routing the required received signal (e.g. polarization) via separate cables to two IRDs located in different rooms/floors of a single family home.
The above-described known system becomes more complicated if the received signal is to be distributed to three or more IRDs (e.g., a single family home having three or more televisions or, more commonly, multiple dwelling units such as apartments, or condos). In this situation, it is known to configure the dual LNB to output a left-hand circularly polarized (LHCP) satellite signal component and a right hand circularly polarized (RHCP) satellite signal component. The LHCP and RHCP components are then routed via separate cables to one or more multiswitches, which in turn routes a selected polarization signal individually to each of a plurality of IRDs. Other systems couple the LNB output to the multiswitch using a single cable approach, wherein the RHCP satellite signal is transmitted at a frequency between 950-1450 MHz and the left hand signal is remodulated to occupy the bandwidth between 1525-2025 MHz, thereby allowing single cable transmission.
The need for a dedicated IRD for each service area (i.e., room or apartment) in existing satellite distribution systems increases cost and complexity. For example, a conventional IRD includes several relatively costly components, including a modem circuit for transmitting billing data (via PSTN telephone connection) to the satellite provider, a power supply, conditional access circuitry and its own protective case. In addition, each IRD requires access to a telephone line connection to support modem communication thereby adding phone-line installation costs. Moreover, the telephone service required to support the call back feature of the IRDs can be quite costly. This may not be cost effective for multiple-room single family home applications.
Installing a home-wide or building-wide cable network capable of distributing the wide L-band 950-1450 MHz signal would be costly. Moreover, such satellite distribution systems are often a source of satellite signal degradation due to improper crimping of the connectors commonly used in the installations. It would therefore be advantageous for a satellite signal distribution system to take advantage of existing communications wiring that may be present in a given home or multiple-dwelling-unit. For example, many homes/buildings are already wired with a cable distribution network designed for distributing relatively narrow-bandwidth cable television signals. However, because the typical cable distribution network was designed specifically for distributing a narrower bandwidth, low frequency cable TV signal, these cables tend to cause amplitude attenuation when they are used to transport relatively wide bandwidth high frequency satellite signals.
One approach to solving the problem of distributing wide L-band satellite signals over existing narrower-band cables has been utilized in various travel industry applications (e.g., hotels, ships, airplanes, trains, etc.). For example, in a cruise ship application, such systems typically employ a plurality of IRDs residing at a common location such as a restricted access cabin on the ship. Each IRD is tuned to receive a single, unique channel, and each IRD includes a radio frequency (xe2x80x9cRFxe2x80x9d) modulator for converting the received satellite signal to an RF modulated signal that is better suited for transmission to the ship""s cabins over the single cable of the ship""s cable TV distribution network. A television in each cabin includes a tuner that selects between the various channels provided via the single cable. However, such systems have limited versatility because, although the cabin viewer may control the tuner residing within their own TV set to receive a channel, the viewer is not able to control the IRD, and is therefore only able to receive one of the channels to which the IRDs are pre-tuned. Moreover, the number of channels received is limited by the number of IRDs installed in the system.
Accordingly, there is a need for a multiple-room, multiple-unit signal distribution system that overcomes the above-described shortcomings of known signal distribution systems. More particularly, there is a need for a signal distribution system that receives a broadcast wide bandwidth high frequency signal at a single input point (e.g., a satellite antenna) and enables the efficient and cost effective distribution of the received wide band high frequency signal to different areas of a single general location (e.g., different rooms/floors of a single family unit, or different units/floors of a multiple-dwelling-unit).
The present invention is embodied in a multiple-room, multiple-unit signal distribution system that overcomes the above-described shortcomings of known signal distribution systems. More particularly, the present invention is embodied in a signal distribution system that receives a broadcast wide bandwidth signal at a single input point (e.g., a satellite antenna) and enables the efficient and cost effective distribution of the received wide band high frequency signal to different areas of a single general location (e.g., different rooms/floors of a single family unit, or different units/floors of a multiple-dwelling-unit). The disclosed signal distribution system can utilize existing relatively narrow bandwidth low frequency cable networks found in many single family homes and multiple-dwelling-units.
A multiple-room, multiple-unit signal distribution system embodying the present invention is adapted to provide access to multichannel digital subscription satellite television programming to a plurality of rooms in a single family dwelling, and may be further adapted to provide satellite television programming to a plurality of dwelling units in a multiple dwelling unit such as an apartment. A plurality of integrated receiver decoder modules supported by a common chassis receive satellite signals from a satellite antenna and filter and supply the signals to a distribution system that is coupled to a plurality of display devices that are located in various rooms throughout the single family home (or to various apartment units in an MDU). A plurality of hand-held remote controllers, each being associated with one of the integrated receiver decoder modules, are used to communicate with and control the associated integrated receiver decoder modules to cause each to supply a desired signal to a desired display device. Each of the remote controllers is adapted to ensure exclusive communication with the associated integrated receiver decoder module and to prevent interference with the operation of the other integrated receiver decoder modules, either permanently, configurably, or by user selection. A single power supply is preferably used to power the co-located integrated receiver decoder modules, and a single modem, is preferably used to report billing information to the satellite provider for each of the modules.
Accordingly, the present invention may be utilized in a transmission system in which information signals are transmitted to a plurality of user locations, wherein each of the user locations includes a plurality of service areas therein. An information signal distribution system at at least one of said user locations includes a central unit having a primary information signal input port that receives primary information signals, said primary information signals comprising a plurality of primary information signal components. The central unit further has at least one output port that outputs to a distribution network selected ones of said plurality of primary information signal components for distribution to each of the plurality of service areas. The central unit houses signal processing circuitry that receives said primary information signal, along with a plurality of coded user selection signals. The signal processing circuitry processing said primary information signal, based on said coded user selection signals, along a plurality of parallel and independent signal paths to independently and in parallel provide any one of said primary information signal components to said at least one output port. The coded user selection signals include a user selection component that identifies one of the plurality of primary information signal components. The user selection information further includes a coded portion that identifies one of said plurality of parallel and independent signal paths.
In the above-recited information signal distribution system, the at least one user location comprises a single family dwelling unit, and said plurality of service areas comprise rooms in said single family dwelling unit. Alternatively, the at least one user location comprises a multiple-dwelling-unit building, and said plurality of service areas comprise dwelling units of said multiple-dwelling-unit building.
The above-recited signal distribution system may further include a plurality of remote user interface units located in at least some of said service areas. The remote user interface units receive said coded user selection signals and provide them to said central unit.
The signal processing circuitry includes decoder modules for each of said plurality of parallel and independent signal paths. The decoder modules independently and in parallel decode said primary information signal to provide any one of said primary information signal components to said at least one output port. The signal processing circuitry further includes at least one shared-resources module that generates shared resources that are shared among said decoder modules. The shared resources may be power resources, conditional access resources that determine what primary information signal components said central unit is authorized to receive, and/or modem resources that provide access to a telephone line for transmitting information gathered by said central unit.
The signal processing circuitry further includes a signal combiner that combines the selected primary information signal components decoded by said decoder modules and provides a combined signal to said central unit output port and said distribution network.
The central unit can further include at least one auxiliary input port that receives auxiliary information signals. The signal combiner therefore also combines said auxiliary information signals such that said combined signal comprises said selected primary information signal components decoded by said decoder modules and said auxiliary information signal. The auxiliary information signal can be an off-air broadcast television signal, a cable television signal, and/or another signal source.
The primary information signal can be packetized streaming digital data comprising various channels of video/audio programming, and the primary information signal components can include the various channels of video/audio programming. The user selection component can include signals representing a user""s selection of one of said various channels of audio/video programming.
The primary information signal can include a wide L-band signal, and each of said decoders comprise an agile RF modulator that modulates said primary information signal component to a narrow bandwidth signal.